The denial of a motion to suppress was reversed where the police officer’s reasonable suspicion for the stop was based on a misapprehension of the traffic law. The officer’s articulated reason for the stop was that he saw a disabled placard hanging from a rearview mirror which he believed to be a violation of a local ordinance, the driver was young and he did not associate young people with disabilities, and he was suspicious that the car was stolen even though police dispatch had radioed him that there was no such theft report. The officer discovered during the traffic stop that there was an outstanding warrant for King’s arrest, and also discovered crack cocaine during a patdown search. Although a local ordinance prohibited posting signs upon the windshield of a vehicle which materially obstructs the view, the court interpreted the word “upon” to require direct contact. A disabled placard hanging from the rearview mirror was not in violation of the ordinance. Because an officer’s mistake of law cannot form the basis for reasonable suspicion to initiate a traffic stop, the denial of the motion to suppress had to be reversed.